The contamination of seabeds has become more problematic as the environment has gradually become more polluted. Pathogenic microorganisms are well known to infect seabeds, which are exposed to toxic waste and other undesirable pollutants. Controlled cultivation of fish, mollusks, crustaceans and other aquianimals has become more prevalent in view of the ever growing scarcity of uncontaminated sources. Such contamination concerns are further complicated by the fact that a number of bacteria have become multi-drug resistant as a result of improper and/or overuse of antibiotics. The emergence of antibiotic-resistant bacteria has become more widespread and has resulted in the necessity to track the spread of such resistant strains and to the initiation of research efforts which seek alternative antibacterial agents which can be used to combat such resistant strains.
Pathogenic Vibrio vulnificus is commonly found in raw oysters and has been associated with the occurrence of shrimp diseases, either as a direct cause of disease, or as a carrier of virus or both. Additionally, bacteria such as Staphylococcus aureus has become resistant to methicillin, leaving only vancomycin as the remaining effective antibiotic against this strain. Virulent strains of enterococcus have emerged which are vancomycin resistant causing an alarming realization of the need to find new antibiotics against this organism. Such pathogenic bacteria are known to be extremely dangerous to humans.
The present invention provides a solution to deputation of bivalves and mollusks by using the marine algae Chaetoceros as a food source for the aquianimals. Chaetoceros spp. provide natural antibiotic properties which cleanse the aquianimal from pathogenic vibrio, thereby making the harvested seafood safe for consumption.
Additionally, there is a need for new antibiotics and pharmaceutical compositions based thereon which are effective against a broad spectrum of bacteria and which are particularly useful against known multi-drug resistant strains of bacteria, including methicillin resistant Staphylococcus aureus, vancomycin resistant enterococcus, Vibrio cholerae and Vibrio vulnificus. Additionally, there is a need for the development of new antibacterially effective agents which can be made inexpensively and which are safe for use in mammals, aquianimals and the like. The present invention provides antibacterial agents which are based on the extracts of the marine algae Chaetoceros. Fractions and isolates of Chaetoceros spp. extracts have been shown to provide antibacterial activity and, in particular are active against methicillin resistant Staphylococcus aureus, vancomycin resistant enterococcus bacteria, vibrio chlorae and vibrio vulnificus. The antibacterially effective extracts of the Chaetoceros algae are believed to either occur naturally in the unicellular algae or are produced by the algae in response to the presence of bacterium and other algae that compete against Chaetoceros for living space.
Pharmaceutical compositions and methods of treating mammals by administering bacterially effective amounts of one or more of the isolates of the Chaetoceros spp. extract are claimed herein.